Depends on who's drag porting...

B/W 55 & 60...

I would say it is possible to obtain HP in the mid 80's range without any 'chemical' assistance.
Probably close to 100 with a little 'soup'

 

Tudors is less than reputable IMHO... (Among others)
He might be close measuring HP at the crank and at sea level...Does he have any dyno curves to share with us?

One thing to keep in mind here... a stage 2 port job from Puppy shop 'A' might be quite a bit different from Puppy shop 'B'...
Typically a stage 2 port job has no port dimension change from stock...just the runners cleaned/smoothed.

Also, porting is not the complete package, only one variable to the equation... The pipe design must match the port setup (RPM) along with adequate carburation, etc, etc, etc.

My $.02

 

so what mods are the most effective at producing the most power on a lt500? just curious?

 

There's no 'one' modification that brings the beast to life... More of a combination of things and/or package.
THere are also many design shortfalls for this motor that need corrected to be a reliable strong running machine.

Porting
Head modification
Piston mods
Bigger carb
Pipe

not to mention the case inserts if your motor has alot of hours on it...

my $.02

 

Air box/filter mod along with a good reed cage. Pyramid or v-force cage
Billet clutch basket

One other part to be aware of is the water pump I've seen a few of them fail.